When fruit is harvested in an orchard, it is commonly placed in rectangular bins which are then loaded onto a trailer specifically designed for carrying such bins. A typical prior art fruit bin trailer has a pair of support rails which are joined by a crossbar at the front end and which usually have an upright stop at the front end to prevent the bins which rest on the rails from falling forward off the trailer. A tongue extends forward from the trailer to a tractor hitch which, together with a wheel-bearing axle near the midpoint of the rails support the rails several inches off the ground.
For ease of loading and unloading, the trailer is typically tilted into a position where the back end of the rails contact the ground. This allows the bins to slide from the ground onto the rails, or vice versa. Endless conveyor chains along the length of each rail driven by a hydraulic motor assist in the sliding of bins up onto or down off the rails.
The lowering of the back end of the rails in a typical prior art fruit bin trailer is accomplished by pivoting the trailer about its axle with a vertical hydraulic cylinder mounted between the front stop and the tongue, which is pivotally connected to the underside of the trailer for this purpose. While this arrangement does lower the rear of the trailer as desired, it also raises the front end. This is undesirable since the incline of the rails is as a result quite steep. Since fruit-filled bins are both bulky and heavy, a steep incline makes a difficult job still more difficult.
Another disadvantage of the pivoting prior art trailer is that the bins on the raised front end of the trailer may be unable to clear low branches. Maneuvering the trailer to avoid the low branches may be time-consuming or impossible, but not doing so will damage the branches, and possibly the trailer.
Still another disadvantage of prior art trailers is that bins can easily fall off the back end of a trailer. Because the back ends of the rails are flat, so as to present no resistance to the normal loading and unloading of bins, they do not prevent accidental unloading. Bins are free to slide backward off the rails while the back ends of the rails are raised off the ground. Since trailers frequently travel over rough ground and unpaved surfaces in fields and orchards, the kind of jarring, bumpy ride which would lead to bins falling rearwardly off the trailer is a common occurrence.
A need has thus arisen for a trailer which is easily loaded and unloaded, which does not interfere with low branches in an orchard or other elements of its surrounding environment, and which holds its load securely so that the load does not slide off the rails during transport.